Coming soon: self-repairing building materials

Washington, April 19 (IANS) Buildings may be capable of repairing themselves in the future. It sounds like science fiction, but scientists are developing self-repairing polymer materials whereby cracks can be sealed automatically. The technology being developed has been inspired by the human body’s ability to repair minor cuts without any external intervention.

There are two such technologies in polymer materials: adhesives and thermal encapsulation. The first involves a series of “stores” of adhesive distributed homogenously throughout the material, so that when the crack reaches one of these nodes, the adhesive is secreted, together with a catalyst, and the crack is closed and the material polymerised.

There are two variants within this technology, depending on whether adhesive-containing microcapsules or tubes filled with adhesive are employed.

INASMET-Tecnalia, a private technological centre in Spain, has worked on this line. It has managed to produce a series of microcapsules and distribute them in a polymeric resin. This was a fundamental step to finding out the difficulties that might arise in the encapsulation process.

The second method, developed by Bristol University, is a project for the European Space Agency (ESA), is very similar. The difference lies in the use of tubes rather than microcapsules filled with adhesive.

The thermal method uses a different repair technology. The material, developed by the University of Sheffield, is a polymeric matrix compound, reinforced with carbon fibres. The polymer matrix, in turn, is made of a solid solution of a thermoplastic polymer and another thermostable polymer.

The development of self-repairing materials is still at initial stages and there is a long way to go before reaching the desired goal. Nevertheless, the results are encouraging.